My zen will lock itself randomly while the button is in the neutral position, and it's a massive pain to unlock. I usually have to flick the switch back and forth rapidly to get to unlock, and it only stays that way for a few seconds before locking up again. I had this problem a few months before and I had to do the above for a week until the player decided get its act together. I've tried resets, firmware and the like. Does anyone know what's up?